Electrical instrument platform for mounting on and removal from an energized high voltage power conductor

ABSTRACT

An apparatus for monitoring and measuring the electrical, thermal and mechanical operating parameters of high voltage power conductors. A toroidal shaped housing, which can be mounted onto an energized conductor, contains all of the necessary electrical instruments to monitor the parameters associated with the conductor. Moreover, the housing includes the processing capability to analyze disturbance and fault events based on these parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application60/623,900, filed Nov. 1, 2004.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus for monitoringand measuring the electrical, thermal and mechanical operatingparameters of high voltage power conductors. More particularly, theapparatus may be mounted onto overhead power transmission lines tomonitor the operation of electrical power systems.

BACKGROUND OF THE INVENTION

Numerous instruments for measuring the operating parameters of powerline conductors have been disclosed in the prior art. For example, U.S.Pat. Nos. 3,428,896; 3,633,191; 4,158,810; 4,268,818; 4,384,289 and4,794,327 (the disclosures of which are incorporated herein byreference) each describe instruments for measuring and analyzing theperformance of particular parameters of overhead power line conductors.Note, the terms power line, transmission line, and conductor are usedinterchangeably herein. Typically, these instruments only measure asubset of the many parameters needed to completely analyze an electricalpower system. For example, prior art instruments may individuallymeasure, but do not monitor: current flow in the conductor, conductortemperature, ambient temperature, conductor tension relative to asupporting tower, and/or conductor sag. To date, none of the prior artinstruments measures or monitors a complete set of the parameters neededto fully describe the operational state of a power conductor. Moreover,prior art instruments do not provide for the sharing of data betweensimilar instruments or multiple ground receiving stations. Rather, theabove prior art references propose that individual instruments gatherdata for transmission through dedicated local ground receiving stationsto central control stations for correlation and analysis. Theseinstruments are simply not capable of simultaneously monitoring andanalyzing many of the operating parameters of a transmission line.

In a system having several measuring instruments each transmitting datato ground based receivers, a means should be provided to ensure thatmore than one instrument is not transmitting at any given time. To avoidinterference and data loss caused by more than one instrumenttransmitting data at a given time, it has been suggested that data couldbe transmitted in finite bursts at random times. However, under thisapproach, the possibility still exists that multiple instruments willtransmit data at the same time.

Therefore, a need exists for an electrical instrument platform which maybe mounted directly on an energized power conductor and is capable ofsimultaneously measuring and monitoring a complete set of parameters ofthe conductor while communicating those parameters to other similarinstruments and also to local or remote ground based processors.

SUMMARY OF THE INVENTION

Accordingly, the present invention meets this need by providing anapparatus for mounting directly on an energized power conductor andwhich is capable of simultaneously measuring and monitoring a full suiteof electrical, thermal and mechanical parameters of the conductor whilecommunicating those values to other similar instruments and also tolocal or remote ground based processors. The present invention mayprocess and analyze data generated by its own instruments, as well asdata received from other such apparatus.

The present invention has the capability to monitor all necessaryparameters, including disturbance events and fault events that may occurduring the operation of a complete electrical power transmission system.The present invention provides complete monitoring by using power linemounted instruments, each capable of simultaneously sensing voltage,current, phase angle and other parameters of an associated conductor andcommunicating the measured parameters amongst these instruments, as wellas to ground based processors.

As another aspect of the present invention, the apparatus incorporatesall of the required instrument components in its housing. The apparatusmay be installed on the conductor without shutting down the powertransmission circuit. The apparatus may monitor the parameters beingmeasured by comparing them against preset levels, and by storing datafor later retrieval and analysis. The measured data may be communicatedin real time, using wireless radio transceivers. Data communicated fromthe instruments to the receiving processors, whether local or remote, isalready in condition for processing. This eliminates the need foraccessories (such as auxiliary transformers, transducers, and the like)otherwise needed for signal conditioning and processing in prior artsubstation monitoring systems. The present invention interrogates eachinstrument in turn so that no two instruments in the apparatus aretransmitting at the same time. This approach mitigates the possibilityof data loss associated with prior art methods. The apparatus may bepowered by the electro-magnetic field generated by current flowingthrough the power conductor to which it is mounted. A stored energymeans (e.g. batteries) may be provided to power the apparatus when thereis insufficient or no current flowing through the conductor.

Advantages of the present invention include the ability to monitor theoperation of a conductor over time, rather than simply making singleshot measurements; the ability to analyze measured data on-board and inreal time; and the ability to draw its power by induction from theconductor. Further, the present invention provides for flexibility inthe measurements which can be taken. Accordingly, the present inventionis a significant improvement over prior art devices in the areas ofprocessing, monitoring, flexibility, communications, and installation.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, reference is made tothe following description and accompanying drawings, in which:

FIG. 1 illustrates apparatus of the present invention mounted on atransmission line;

FIG. 2 is a top-view of the apparatus shown in an open position readyfor mounting on a transmission line;

FIG. 3 is a top-view showing the magnetic core mounted in the lower-halfshell of the housing of apparatus in accordance with the presentinvention;

FIG. 4 is a side-view showing the ends of the magnetic core of theapparatus when in the open position,

FIG. 5 is a top-view showing the battery pack mounted in the upper-halfshell of the housing of the apparatus;

FIG. 6 is a top-view showing the Rogowski coil for measuring currentmounted in the upper-half shell of the housing of the apparatus;

FIG. 7 illustrates the pick-up lead for measuring voltage mounted in thehousing of the apparatus;

FIG. 8 illustrates one of two temperature probes for measuringtemperature mounted in the housing of the apparatus;

FIG. 9 is a top-view showing the radio antenna used for both wirelessand cellular communications mounted on the housing of the apparatus; and

FIG. 10 is a schematic diagram of a conventional transmission linemodel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the apparatus and method according to thepresent invention will be described with reference to the accompanyingdrawings.

I. Physical Description

The present invention provides an apparatus for monitoring and measuringthe electrical, thermal and mechanical operating parameters of highvoltage power conductors. More particularly, the apparatus is for use insystems that are mounted onto overhead power transmission lines and thatmeasure parameters necessary to monitor the operation of single-phasecircuits, three phase circuits, and entire electrical power systems.

The invention has a torus shaped housing with a metallic outer surface.FIG. 1 illustrates one embodiment of the present invention mounted on atransmission line. The housing incorporates all thecomponents/instruments required to measure these parameters. Theinvention not only includes the means to monitor various parameters, butalso includes the means to locally record the parameters for laterretrieval, compare them against preset levels, and analyze disturbanceand fault events based on these parameters. As described more fullybelow, the housing includes an embedded information processingcapability to perform a complete analysis of the transmission line.

The toroidal housing has two half-sections that are hinged such that thehousing can be split open to mount the apparatus onto a conductor, andthen closed over the conductor when in the installed position. FIG. 2 isa top-view of an embodiment of the present invention shown in an openposition ready for mounting on a transmission line. The axial center ofthe housing includes a central supporting member, or “hub,” whichthermally isolates the conductor from the housing. This hub fixes thehousing to the conductor so that the housing will not rotate around ormove along the conductor.

The housing typically includes electrical instruments for measuring theelectric current flowing through the conductor, measuring the electricpotential (voltage) of the conductor relative to ground, determining thephase relationship between the measured current and voltage, measuringthe temperature of the conductor, sensing the pitch angle of theconductor, and/or sensing motion perpendicular to the longitudinal axisof the conductor. For example, FIG. 6 shows a top-view of a “Rogowski”coil 610 for measuring current mounted in the upper-half shell of thehousing. FIG. 7 illustrates a pick-up lead 710 for measuring voltagemounted in the housing. The phase relationship between the current andvoltage can readily be determined by comparing the phase between similarpoints (such as the peaks) on each waveform. The present apparatus mayuse an inclinometer to sense the pitch angle and an accelerometer tosense motion along and/or perpendicular to the axis of the conductor.

One or more temperature probe(s) are mounted in the hub area of thehousing to measure the temperature of the conductor and/or the ambienttemperature. FIG. 8 shows a temperature probe 810 for measuring thetemperature of the conductor. The temperature probes are thermallyinsulated so that the housing does not impact the measurements.

Further description of the instruments and measurements performed by theapparatus may be found in the commonly owned International ApplicationNo. PCT/US2005/025670, entitled “Dynamic Line Rating System withReal-Time Tracking of Conductor Creep to Establish the Maximum AllowableConductor Loading as Limited by Clearance,” filed Jul. 20, 2005; whichis incorporated herein by reference.

More specifically, the apparatus may provide the following data:

-   -   a) voltage;    -   b) current;    -   c) phase angle between the voltage and current;    -   d) the power flow demand resulting from the voltage and current;    -   e) the power flow reactive demand resulting from the voltage and        current;    -   f) the energy rate due to current flowing through the conductor        resulting from the voltage and current;    -   g) the reactive energy rate due to current flowing through the        conductor resulting from the voltage and current;    -   h) the temperature of the conductor in one or more locations        around the circumference of the conductor;    -   i) the vibration of the conductor in a direction perpendicular        to the conductor; i.e. power line galloping and Aeolian        vibration;    -   j) the pitch angle of the conductor relative to horizontal; and    -   k) other parameters that characterize the real time operational        state of a power conductor and can communicate real time reports        to remote, ground based systems.

Processors in the apparatus can analyze the voltage and currentwaveforms to derive further information such as: disturbance events,fault events, and detection and mitigation of corona effects on thevoltage and current measurements. Most of the calculations, processing,and analysis disclosed herein may be performed by software running onone or more processors located in the housing of the apparatus. Theseprocessors may be part of a processing unit 530 which might be fit intothe housing as shown in FIG. 5. Analysis software for performing thesecalculations may be resident in the processors and/or stored in amemory. An exemplary memory or storage unit 540 may be fit into thehousing as shown in FIG. 5. As mentioned above, such a storage unit maybe used to record the data being collected by the instruments in theapparatus.

Data Transfer and Communication

The apparatus includes a communication unit for transmitting andreceiving various measured and analyzed parameters to other similarapparatus at different locations on the conductor. Communications may beconducted in real-time, e.g. using wireless radio transceivers, and/ormay be on-demand using, for example, cellular telephone technology. FIG.9 is a top-view of a communications transceiver 910 used for bothwireless and cellular communications mounted on the housing of theapparatus in accordance with the present invention.

As discussed previously, prior art power line instruments require local,ground based devices to coordinate the collection of data, and toforward this data to remote processing units. Such ground based devicesmay be mounted on towers, or placed on pads at ground level. The presentinvention, because it is fitted with a communications transceiver, canbe used without local ground based equipment.

Additionally, as part of its analysis capability, the present inventioncan receive global positioning signals (GPS). Typically, the time stampfrom the GPS signal is extracted and used to ensure accuratecalculations. A GPS unit may be included with the communicationstransceiver 910 shown in FIG. 9.

Another aspect of the present invention is data transfer using atime-multiplexed methodology. The present invention uses a modified timedivision multiple access (TDMA) data transfer protocol to transfer databetween devices in the system. Data output from the devices, includingto and from ground based processors, is cast in terms of a defined datacommunications protocol. The various data values produced by a device,as well as communication management parameters associated with thedevice (such as its address) are included in the data communicationsprotocol. One device is selected to be the data transfer controller,i.e. the master device. All other devices are slaved to the masterdevice for any data transfers. Typically, a ground based processor wouldbe designated as the controller.

The data communications protocol defines a message frame, a messageaddress and a message body. Each device in the system is assigned aunique system address. The message body may contain a command or a dataresponse to the command. The controller sends an interrogation pollcommand simultaneously to all other devices and only the device whoseaddress is contained in the message may respond. This methodologyprevents data collisions thereby mitigating the loss of data. The formatand commands used in the data communications protocol are describedbelow.

All devices in the system are capable of decoding digital messagesconforming to this protocol. In addition, each device may operate asboth a controller and as a slaved device. This allows the system torelay messages between devices that might otherwise be out of the directradio communication range.

The present invention also uses file and data formats and file namingconventions conforming to the IEEE C37.111-1992 “Standard Common Formatfor Transient Data Exchange (COMTRADE) for Power Systems.”

Also, the present invention allows for its instrument and/or analysissoftware to be updated without removing the apparatus from the powerconductor. Such software updates could be uploaded to the housingthrough the communications transceiver and stored in on-board memoryand/or used by the processors.

Power System

The present invention derives it primary power from the energizedconductor onto which the housing is mounted. The housing contains amagnetic core which is coupled by induction to the electromagnetic fieldgenerated when current flows in the power line conductor. FIG. 3 is atop-view showing the magnetic core 310 mounted in the lower-half shellof the housing. The magnetic core extends around the interior of thehousing to surround the conductor. The core is divided into twomagnetized sections such that opposed pole faces are separated when thehousing is “opened” and in contact with each other when the housing is“closed” and mounted onto the conductor. FIG. 4 is a side-view pictureshowing two ends 410, 420 of the magnetic core of the present apparatuswhen in the open position. The magnetic core has a minimal set ofsecondary power pick-off coils and power conditioners that are used topower the components in the housing.

As a secondary power source, the apparatus includes a rechargeablebattery to power the components in the housing when there isinsufficient or no current flowing through the conductor. FIG. 5 is atop-view showing the battery pack 510 mounted in the upper-half shell ofthe housing of the present apparatus.

The current level in the conductor is monitored by sensing circuitry inthe housing to determine whether the flow is above predetermined minimumthreshold values. The apparatus is powered by the battery when the linecurrent is below a first threshold value. If the current flow is abovethis first threshold, the apparatus may be powered by electromagneticinduction from the conductor. When the current is above a secondthreshold value, excess induction current is used by a charger in thebattery pack 510 to charge the battery. If an insufficient currentcondition (i.e. below the first threshold) persists in the conductorbeyond a predetermined time limit, the apparatus can reduce thefrequency of data transmission to conserve battery power. If the batteryvoltage drops below a second threshold level, all battery-poweredtransmission is stopped until the battery is recharged.

Because the apparatus is attached directly on the power conductor, andmeasures current and voltage from the electrical and magnetic fieldsurrounding the conductor, the present invention eliminates the need formany of the auxiliary ground based transformers, transducers, testswitches, terminal blocks, fault monitors and hard wiring required inprevious power monitoring systems.

II. Data Processing

A. Disturbance Event Processing

The processing performed by the present invention is capable ofanalyzing instrument inputs to produce at least the following types ofdisturbance reports:

-   -   a. Disturbance location reports based on 60 Hz voltage (V) and        current (I) measurements from one end of a line;    -   b. Disturbance location reports based on the Takagi algorithm        using data from one end of a line;    -   c. Disturbance location reports based on phasor data from both        ends of a line;    -   d. Disturbance location information based on ratios of currents        from both ends of a line; and    -   e. Disturbance location reports based on traveling waves        captured at both ends of a line.

The terms disturbance and fault are used interchangeably herein.However, disturbance recording typically requires data acquisition forat least five minutes while fault recording generally captures data overintervals of less than one second. Accordingly, fault recording may beviewed as a subset of disturbance recording.

Because most faults are temporary and the location of a fault is notalways easy to find, it is advantageous to have accurate fault locationinformation. Nevertheless, utilities still routinely examinetransmission line hardware via helicopters to locate a fault. It oftentakes a long time to find the site of a fault, even for common problemssuch as cracked insulators from arc-over due to lightning strikes.

The distance along a transmission line to a fault can be calculated fromone end of the line using voltage and current measurements. Faultvoltage and current data is used to calculate the reactance from themeasuring site to the fault and establish the distance based on thereactance per mile of the transmission line. Reactance is used ratherthan impedance so as to minimize the effect of fault resistance.However, this technique does not entirely eliminate the effect of faultresistance because of the voltage drop caused by line current flowinginto the fault resistance from the other end of the line. The error inthis type of calculation can be up to 5 or 10 percent. For example, anerror of ±5% on a 100 mile line would be ±5 miles. Although this doeslimit the search range, a more accurate calculation is needed.

The Takagi algorithm was first published in 1980 and has proven to bequite accurate. This algorithm was first applied in the U.S. in theSchweitzer Distance Relay and remains today the preferred algorithm forfault location based on voltage and current measurements from one end ofa line. However, it is still dependent on the accuracy of the voltageand current inputs from one end of the line.

Fault location can also be accurately computed using phasor informationfrom both ends of a transmission line. In this case, the locationcalculation is independent of the fault resistance and is thereforeimmune to the effects of out-of-phase sources feeding into the fault. Inthis calculation, remote phasors are synchronized analytically in adouble-ended algorithm, thereby eliminating the need for phasorsynchronization. This is accomplished by expressing the voltage angle atone end of the line as a known measured angle plus an unknownsynchronization error. Applying this approach to a conventionaltransmission line model, as shown in FIG. 10, results in three unknownparameters: the synchronization angle (error), the location of the fault(m), and the fault resistance (R_(fault)). FIG. 10 shows that the faultvoltage (V_(fault)) can be expressed by two equations written in termsof the fault current flowing from each terminal of the line(I_(From))_(fault) and (I_(TO))_(Fault). The resistance can beeliminated mathematically from these equations by equating the twoexpressions in terms of the fault voltage. Separating the complexequations into real and imaginary parts results in two equations withtwo unknown parameters: the synchronization error between the remotemeasurements and the fault location. Both of the unknown parameters canbe computed using the two equations.

Another method for calculating fault location, especially for longertransmission lines (over 300 miles), is based on the ratios of thecurrents feeding into the fault as measured from both ends of the line.A fault in the center of the line would result in the some current atboth ends. This calculation must also take into account the impedance tothe generating sources at each end of the line and the currentmeasurements must be corrected for offset.

The distance to a fault can also be determined by capturing a travelingwave at both ends of the line. Lightning strikes are a common cause oftraveling waves on transmission lines. Typically, the waveform of alightning surge voltage on a high voltage power transmission lineflattens as the voltage surge travels further along the transmissionline. The conventional method for picking up traveling waves is to usean inductor or high frequency transformer in series with a voltageconnection between the power line and the case of the measuringinstrument. However, in the present invention, the voltage waveform ismonitored by means of capacitive coupling. The apparatus may include aconductor to short (or alternatively, a capacitor to couple) the powerline to the housing. Current will flow out from the housing to ground inproportion to the surface area of the housing. The voltage may bemeasured from this current flow.

B. Data Acquisition Triggering Schemes

A triggering mechanism is required to capture fault current and voltagewaveforms. The trigger mechanism should be based on a change from a zerostate to some value (referred to as all-or-nothing sensing) rather thanon particular signal levels because the operating conditions of the linedemand different level settings for different operating conditions.

One method used in the present invention is to trigger far-end faultdata capture upon a current reversal of the current direction to feedthe fault. This method requires a phase comparator to compare theprevious cycle with the current cycle on a rolling half cycle basis. Inthis situation, fault data is only needed at one end of the line andtherefore eliminates the need to transmit a trigger to the other end.However, triggering must be relayed between all three phases within 5cycles of 60 Hz in order to capture voltage and current waveforms withat least 5 cycles of pre-fault; assuming that the detecting phase has 10cycles of pre-fault.

Pre-fault and fault data should be captured with a frequency response of1200 Hz (or better) in order to capture breaker re-strikes. Anyanti-aliasing filters should be of the linear phase response type so asto eliminate overshoot and ringing on step inputs. The correspondingband limits will be at the 6 db points. Sixty cycles of post-fault datashould also be captured in order to include the re-close and potentialbeginning of a power swing, but only the 60 Hz component needs to berecorded. If the fault still exists upon re-closing, the response shouldrevert back to 1200 Hz in the pre-fault and fault interval beforedropping back to 60 Hz in the post-fault period.

If a current reversal is detected at both ends of the line, the faultrecord captured for that line section should be deleted within a secondor so after the fault record is captured. Those fault records should bedeleted because the fault is not within those line sections that havecurrent reversals at both ends. The fault will be in the Hue sectionthat has a current reversal at one end only. This is a definiteimprovement over standard fault recorders that capture data at everyfault recorder site. It then becomes necessary to find the record thatis closest to the fault for analysis.

The present invention may additionally, or alternatively, use one ormore of the following triggering methods:

-   -   capture data following a fault to obtain data on instabilities;    -   use a timed impedance trajectory instrument for power swings;    -   trigger on under-frequency fur under-frequency conditions;    -   trigger on timed positive sequence under-voltage for voltage        collapse; and    -   trigger on period jumps in 60 Hz waveforms to capture data on        power redistributions following a reconfiguration of the system        after a fault or loss of generation or transmission. A change in        system configuration causes a change in voltage angle at every        node in the system so as to conform to the new conditions for        power flow.

C. Real Time Voltage Phase Angle Measurements

The present invention measures the voltage phase angle once a second andtransmits it to an operations center on a real time basis. The angle isdetermined by recording the time difference between the exact time [to aresolution of 10 microseconds (0.22 degrees of 60 Hz)] of themeasurement to the next positive zero crossing of the voltage waveform.Simultaneous measurements could be taken at both ends of the line todetermine the phase angle from one end of the line to the other.

The voltage phase angle M may be calculated from the power flow P bysolving the following equation:P=V_(S)V_(R) sin(M)/Xwhere V_(S) and V_(R) are the sending and receiving end voltages, X isthe reactance between these two voltages, and M is the angle by whichV_(S) leads V_(R).

D. Power Swing Measurements

Ideally, disturbance recorders should be installed at every backboneinterconnection between the 10 NERC (North American Electric ReliabilityCouncil) regions in the U.S. in order to rapidly analyze disturbancesand improve reliability. This need has been largely ignored over thepast two decades because utilities have no incentive to improve systemreliability and consistently face obstacles to new transmission linesand generating plants. System disturbances can be described as: powerswings, out-of-step conditions, load shedding, or voltage collapse.

Shocks to a transmission system may be caused by faults, loss ofgeneration, or tripping a line. Such shocks may cause power swings(oscillations) whereby power flows back and forth through a line. Powerswings may be a short duration “instability” swing which quicklynormalizes or a sustained “oscillation” in the bus voltage and linecurrent. Data on the character, duration, and period of a power swing isvaluable in preventing future power swings. Power swings are oftenrelatively slow events, typically having a period of around 15-20 cyclesof 60 Hz. For example, the power may propagate in one direction for aperiod of 15 cycles and then back in the other direction for 15 cycles.It is only necessary to record the RMS (root mean squared) currentvalues of each cycle of 60 Hz. Recording should continue for one or twominutes, or until the power swing stops.

If allowed to continue, a power swing may result in an out-of-stepcondition when one or more generators slip a pole. This out-of-stepcondition severely strains generator shafts and affected machines mustbe inspected for damage. Generators typically include damping to preventsuch oscillations, but the required damping factors are not known to ahigh degree of certainty. The data collected for a power swing willindicate the degree of damping applied.

An under-frequency condition occurs when there is insufficient power tosupply the existing load. This occurs when a major source of power islost; such as when a major line trips out or a major generator drops offline. Under such conditions, load shedding is practiced in order topreserve balance in the system. Frequency relays are used to trip outsections of load at particular frequencies as the frequency decreases.For example, the first relay might trip out at 59.8 Hz, the second at59.4 Hz and a third at 59.2 Hz. Shedding continues until the frequencybegins increasing back towards 60.0 Hz. The frequency is typicallyrecorded to an accuracy of 0.01 Hz in order to verify the performance ofthe load shedding relays.

When a line trips out, the operator reconfigures the system and reroutespower over the new system configuration. To increase the transmissioncapacity of a system, capacitors have been installed on manytransmission lines. However, these lines are more sensitive to anoverload, which in turn makes the system more susceptible to a voltagecollapse. It is therefore important to monitor line loading and voltagelevels throughout a power system so that cascading events, such as avoltage collapse, can be understood and prevented.

E. Data Acquisition for Fault Location

As discussed previously, the present invention may acquiredisturbance/fault location data based on a method of capturing thearrival time (to the nearest microsecond) of traveling waves at bothends of a line section. The critical factors in this method are toprovide accurate time synchronization between the ends and inter-endcommunication. A GPS receiver may be used for the time synchronizationby combining the “time of day” serial message and the 1 pps time strobein the GPS signal. The inter-end communication can be by any convenientmeans and does not have to be in real time.

The distance to the fault from the two ends of a line section are givenby:Distance from end A=(linelength/2)+(T1A−T1B)*V/2Distance from end B=(linelength/2)+(T1B−T1A)*V/2wherein the distance is calculated in miles; linelength is the length ofthe line section in miles; A and B designate each end of the linesegment; T1A and T1B represent the respective arrival times at each endfor the first occurrence of the traveling wave; and V is the speed oflight (186,280 miles per second).

The present invention uses a Rogowski coil to pickup the current signalin the line section. The current, rather than the voltage, should beused to detect the traveling wave. The magnitude of the current signalwill be the value of the voltage wave divided by the characteristicimpedance of the power line (approximately 500 ohms).

The current signal is converted to voltage and passed through a 30 kHzsingle pole, high pass filter. The signal is then clipped to preventoverdriving the system's electronics. The signal passes through a 350kHz single pole low pass filter to limit the bandwidth for an improvedsignal to noise ratio. Note, a 350 kHz filter is used to pass onemicrosecond rise time pulses, which roughly correspond to the distancebetween transmission towers.

The pulse detection circuit should include an adjustable thresholddetector to permit triggering on the lowest expected input current forthe traveling wave. Primary current pulse magnitudes on a 345 kv line(200 kv to ground) should range between 56 and 400 amperes depending onhow far the fault is located from the end of the line; assuming a 100mile section. The magnitude of a voltage pulse versus distance is givenby the following formula:E=E₀/(KSE₀+1)wherein E₀ is the initial voltage in kilovolts, S is the travel distancein miles, and K is an empirical constant.

Once a pulse has been detected, the pulse detection circuit must lockoutfor one second to prevent the detection of subsequent reflections andbreaker operations. It should be noted that traveling waves could begenerated by switching operations and faults outside the monitoredsection. Therefore a means must be provided to verify that the detectedwaves are from a fault in the section of line being monitored.

To verify that a fault did in fact occur within the monitored linesection, a phase comparison scheme is recommended. The phase comparisontechnique compares the arrival times of the first positive zero crossingof the current waveform at each end of the line following the receipt ofa traveling wave. If the fault is within the monitored section of line,the times will be nominally different by 180 (+/−90) degrees of 60 Hz.The 180 degree difference stems from current being fed from both ends ofthe line into the fault. Otherwise, the currents at both ends would bein phase. It is expected that the phase information can be communicatedfrom one end of the line to the other within a second. This will allowfor verification of the fault around the time the pulse detectors'one-second-lockout interval ends.

III. Disturbance Reports

Ideally, a system operator will receive a complete disturbance reportafter a fault occurs so that repair crews can be informed anddispatched. Unfortunately, prior art fault recording devices can onlyprovide records consisting of traces of 60 Hz waveforms for the relayengineers to analyze. Clearly defined fault information sets, such aslisted below, are generally not available until the relay engineersanalyze these traces.

Advantageously, the present invention can capture fault data waveformsand perform an automatic analysis on the data so as to extract theinformation required for a fault report. As discussed above, thisanalysis is performed by software running on one or more processors inthe apparatus. The present invention can provide disturbance reportswhich include the following fault data:

-   -   1. Date and time of fault (e.g. to the nearest second)    -   2. Nature of fault (e.g. temporary or permanent)    -   3. Type of fault:        -   a. Three-phase        -   b. Phase-to-phase (e.g. 1-2, 2-3, 3-1)        -   c. Two phase-to-ground (e.g. 1-2-G, 2-3-G, 3-1-G)        -   d. Phase-to-ground (e.g. 1-G, 2-G, 3-G)    -   4. Maximum fault amperage    -   5. Time to clear the fault (e.g. in cycles of 60 Hz)    -   6. Damage estimate (e.g. low, medium, high)

A fault should be considered permanent if the fault still exists uponre-closing the line. The fault is considered temporary if it is notpresent upon re-closing. Re-closing may be automatic or manual. Manualre-closing is preferable for extremely high voltage lines wherere-closing on a fault could cause significant damage. As used herein,re-closing refers to the act of resetting, reconnecting, and/orre-powering a line after the line has been opened such as when a faultoccurs which trips a breaker/relay in the line.

The type of fault can be ascertained by noting which phases have faultcurrent. The presence of a zero sequence component during the faultindicates that a ground is involved in the fault. A zero sequence iscomputed as follows:E₀=(E_(a)+E_(b)+E_(c))/3 where a, b, c, each represent a phaseThe maximum fault amperage is determined by which phase has the maximumcurrent during the fault. The time to clear the fault is the timeinterval from the beginning of the fault current to when the faultcurrent is no longer present (i.e. a breaker is open). Damage estimatescan be made by calculating a value KA², where K is the number of cyclesto clear the fault and A is the value of fault amperes (in 1,000 s).This value is correlated to an expected level of damage which allows adispatcher to tell a repair crew what to expect at the fault site.IV. Data Communications ProtocolIntroduction

This section describes the data communications protocol used by thepresent invention. Data exchange can occur between: two apparatus(electrical instrument platforms); an apparatus and a ground station;and between processors (microcontrollers) within an apparatus. Forexample, the power supply's processor may communicate with the mainboard's processor.

The apparatus normally communicates using wireless radio communicationsystems. A hard-wired connection is provided for configuration andmaintenance purposes via a “Configuration and Test” port. This port usesa three wire version of the RS 232 signal format (see Tables 1A and 1B)to connect with a laptop computer. This port is used when the wirelesssystem in the electrical instrument platform is a cellular-basedtelecommunication system.

TABLE 1A Computer with DB25 Connector RS232 Pin Assignments (DB25 PCsignal set) Pin 1 Protective Ground Pin 2 Transmit Data Pin 3 ReceivedData Pin 4 Request To Send—Not Required Pin 5 Clear To Send—Not RequiredPin 6 Data Set Ready—Not Required Pin 7 Signal Ground Pin 8 ReceivedLine Signal Detector (Data Carrier Detect)—Not Required Pin 20 DataTerminal Ready—Not Required Pin 22 Ring Indicator—Not Required

TABLE 1A Computer with DB9 Connector RS232 Pin Assignments (DB9 PCsignal set) Pin 1 Received Line Signal Detector (Data CarrierDetect)—Not Required Pin 2 Received Data Pin 3 Transmit Data Pin 4 DataTerminal Ready—Not Required Pin 5 Signal Ground Pin 6 Data Set Ready—NotRequired Pin 7 Request To Send—Not Required Pin 8 Clear To Send—NotRequired Pin 9 Ring Indicator—Not RequiredConventions And Terminology

The following conventions are used throughout this specification:

-   -   1. Single ASCII characters are enclosed in single quotes;    -   2. ASCII strings (two or more characters) are enclosed in double        quotes; and    -   3. HEX values are preceded by 0x.

Communicating devices, such as main controllers, power supplycontrollers, maintenance laptop computers, ground stations or “masterstations” are each referred to herein as communicating “units”.Communications occur when an “external” unit transmits a message to a“receiving” unit. Messages may be “requests” for data, or may be“commands” to cause the receiving unit to take some action such aschange configuration parameters, reset the internal clock, etc. . . . .

Data Transpon Link Format

Device Identification

Each electrical instrument platform “unit” is assigned a unique baseaddress, which is downloaded into the devices' firmware. The address isa fifteen (15) bit quantity transmitted as four ASCII character bytes.The address settings are selected as HEX numerals starting at 1 (one) upto 7FFF (representing 32,767 possible addresses). The upper bit isreserved for data routing within the device.

Data Link Format

The protocol uses a 10 bit character frame. The default communicationssetup is:

-   -   Baud Rate: up to 115 kbaud    -   Start Bits: 1    -   Data Bits: 8    -   Stop Bits: 1    -   Parity: None        Data Transport Session Control

The electrical instrument platform employs a point to is multi-pointcommunications protocol. The system design assumes one master controlledas an “external” unit. One master controller can communicate withmultiple recipients.

Data transport sessions begin when the external unit polls a recipientunit. The polled device responds when its unique address is detected inthe poll message. The response includes the recipient's address. It isassumed that there is only one external device to receive the message.

The electrical instrument platform microcontrollers process one commandat a time. If a laptop computer is connected to the field test port,there is a possibility that commands could arrive on both the wirelessport and the field test port at the same time. In that case, theprocessor will handle a message from the first port, complete themessage turn-around before processing a message on a second port. Theports are scanned sequentially.

Data Interchange Format

Data is transmitted as a comma-delimited, ASCII-encoded HEX stringformatted record. The ASCII string is transmitted as a continuous stringwith no extra spaces, carriage returns or form feeds between characters.

Data Format—General

The data message is defined by the packet format shown in Table 2 below.Each device is permitted to maintain specific information in each fieldof its message.

TABLE 2 Protocol Format Generic Structure # Values: Bytes Context ASCIIHEX Description 1 <STX> Cntl B 0x02 Start of Message Packet 4 AAAA“1”-“FFFF” 0x31- 16 Bit Device Address 0x46464646 1 delimiter ‘,’ 0x2CASCII comma field delimiter 1-m Field 1 Variable length data field 1delimiter ‘,’ 0x2C ASCII comma field delimiter 1-m Field 2 Variablelength data field 1 delimiter ‘,’ 0x2C ASCII comma field delimiter 1-mField n add additional fields with delimiter 1 delimiter ‘,’ 0x2C ASCIIcomma field delimiter 2 CS “00”-“FF” 0x3030- 8 Bit checksum calculation0x4646 1 <EOT> Cntl D 0x04 End of Text Character Notes: 1. The checksumis the MOD 256 addition of the characters in the message, including thefirst Byte <STX>. 2. The address field contains the ordinal value of theHEX address. For example, if the unique address is HEX ‘1’, the returnaddress field from the IED will contain the ASCII representation for theHEX value 1, which is “1” or 0x31.Message Formats

The electrical instrument platform incorporates several microcontrollersthat communicate with each other. Communications dialog consists ofrequests and commands. A request is a message code that causes therecipient to send a particular data block. A command is a message thatinstructs the recipient to carry out a specific activity. Table 2.6 is alist of the valid message codes.

Message Routing

Message Addressing

The power supply controller hoard has three ports:

-   -   The “radio” port that is normally used for external        communications. The radio port is used by the spread spectrum        radios and also the cell-phone radio.    -   The “Field Test and Maintenance” port is used for external        communications. The field test port allows a laptop computer to        be connected with the electrical instrument platform for field        setup and testing. The field test port can be active at the same        time as the radio port.    -   The inter-processor communications port. This port connects the        power supply controller with the Main Controller.

Message routing is controlled by the power supply and communicationsexpansion controller. This controller and the main controller both havethe same 16 bit address. When bit 16 of the address is set, the messageis routed to the power supply controller. When bit 16 is clear, themessage is routed to the main controller.

Message Sequencing

Message transactions are processed sequentially, one message transactionat a time. When a message arrives at the power supply controller,whether it is routed to the main controller or to itself, its completeprocess shall be completed before a second message can be processed.Should a second message arrive before the response has been transmittedfor the first message, the second message shall be held in a wait bufferuntil the first transaction has been completed.

TABLE 3 Valid Message Codes # Values: Bytes Context ASCII HEXDescription 1 <STX> Cntl B 0x02 Start of TNP Message Packet 4 AAAA“0001”- 0x30303031- 16 Bit Device Address “FFFF” 0x46464646 1 delimiter‘,’ 0x2C ASCII comma field delimiter 2 Poll Type “AA” 0x41 0x41 AnalogAlarm Configuration Command 2 Poll Type “AC” 0x41 0x43 AnalogConfiguration Request 2 Poll Type “AD” 0x41 0x44 Address ConfigurationCommand 2 Poll Type “AH” 0x41 0x48 Analog Historical Data Request 2 PollType “AN” 0x41 0x4E Analog values data request 2 Poll Type “AR” 0x410x52 Analog Alarm Report From Main Controller 2 Poll Type “AS” 0x41 0x53Autoscaling Command 2 Poll Type “BC” 0x42 0x43 Battery Charger thresholdconfig Reg/Com 2 Poll Type “CA” 0x43 0x41 Offset Calibration Command 2Poll Type “DC” 0x44 0x43 Discretes Configuration Req/Com 2 Poll Type“DI” 0x44 0x49 Report Discrete Input Status 2 Poll Type “EN” 0x45 0x4EEnergy Data Request (kW/kVar) 2 Poll Type “FT” 0x46 0x54 Send FFTCoefficients 2 Poll Type “GP” 0x47 0x50 Send Power Supply Data Main toPower Board 2 Poll Type “GS” 0x47 0x53 Got Discrete Alarm Status FromMain Controller 2 Poll Type “HD” 0x48 0x44 Erase Historical Data Command2 Poll Type “LO” 0x4C 0x4F Start Loader Command 2 Poll Type “MA” 0x4D0x41 Metering Alarm Configuration Command 2 Poll Type “MC” 0x4D 0x43Metering Configuration Req/Com 2 Poll Type “MH” 0x4D 0x48 Meterhistorical Data Request 2 Poll Type “MS” 0x4D 0x53 Meter Analog AlarmStatus from Main Controller 2 Poll Type “OL” 0x4F 0x47 Communications OnLine Status Report 2 Poll Type “PC” 0x50 0x43 Serial Port ConfigurationReq/Com 2 Poll Type “RS” 0x52 0x53 Reset all Accumulated(s) kWhr etc 2Poll Type “SA” 0x53 0x41 Save Configuration Command 2 Poll Type “SC”0x53 0x43 Site Specific Configuration Req/Com 2 Poll Type “SN” 0x53 0x4EUnit Serial Number Request 2 Poll Type “SP” 0x53 0x50 Send Power SupplyData Power Board to Main 2 Poll Type “TS” 0x54 0x53 Time Sync 2 PollType “WA” 0x57 0x41 Send Amp Waveform 2 Poll Type “WC” 0x57 0x43Waveforms Configuration Req/Com 2 Poll Type “WV” 0x57 0x56 Send VoltageWaveform 1-m Opt. flds. additional fields with delimiters before andafter 2 Chcksum “00”-“FF” 0x3030- 8 Bit checksum calculation 0x4646 1<EOT> Cntl D 0x04 End of Text Character

Outgoing messages are always routed through the same port that they areentered through. This means that when a “radio” port message is receivedby the power supply controller, the response is sent out of the sameport. When a message is received on the field test and maintenance port,the response is routed out of that port. When a message arrives on theradio port at the same time that a message is being processed via thefield test and maintenance port, the radio port message is held in thewaiting buffer until the currently processing message transaction iscompleted.

Error Handling

If a received message is corrupted, the recipient should reject the datastring as not conforming to specifications. This may occur for one oftwo reasons:

-   -   1. Two devices have been provided with the same address;    -   Corrective Action: Change one of the devices address.    -   2. The poll message originating with the ground station was        corrupted after reception by the first device;    -   Corrective Action: Retry the poll message.        Specific Message Formats        Data Message Description

The electrical instrument platform message, in addition to its 16 bitdevice address, provides the following data in its message packetresponse to the unique address poll:

AN—Analog Data Request

The Analog Data Request can be initiated by any microcontroller in thesystem. The recipient decodes the message, and responds with a validdata block.

-   -   poll→<STX>address, AN, {start channel}, {end channel}, CS<ETX>    -   valid channels are 0 to 26 (for a list of the channel        assignments see io_chan.h)    -   start channel must be less than end channel    -   if the start channel field is empty, the start channel will be        the first analog input channel, channel 0    -   if the end channel field is empty, the end channel will be the        last analog input channel, channel 25    -   response→<STX>address, AN, start channel, end channel, first        requested channel value, . . . , last requested channel value,        CS<ETX>    -   values are floating point    -   any channels not enabled in the configuration are empty        ME—Metering Data Request

The Metering Data Request can be initiated by any microcontroller in thesystem. The recipient decodes the message, and responds with a validdata block.

-   -   poll→<STX>address, ME, CS<ETX>    -   response→<STX>address, ME, voltage, current, watts, vars, phase        angle, CS<ETX>        EN—Energy Data request

The Energy Data Request can be initiated by any microcontroller in thesystem. The recipient decodes the message, and responds with a validdata block.

-   -   poll→<STX>address, EN, CS<ETX>    -   response→<STX>address, EN, Whr in, V Arhr in, Whr out, V Arhr        out, CS<ETX>    -   any channels not enabled are empty        DI—Digital Data Request

The Discrete Input Data Request can be initiated by any microcontrollerin the system. The Recipient decodes the message, and responds with avalid data block.

-   -   poll→<STX>address, DI, {start channel}, {end channel}, CS<ETX>    -   valid channel numbers are 0 to 27 (0 to 26 are actual digital        inputs; 27 is the battery charger error status)    -   start channel must be less than end channel    -   if start channel is empty, then the start channel is 0    -   if end channel is empty, then the end channel is 27    -   response→<STX>address, DI, first requested channel value, . . .        , last requested channel value, CS<ETX>    -   values are 0 or 1    -   channels that are not enabled in the configuration are empty        TS—Time Synch Command

The Time Sync Command can be initiated by any microcontroller in thesystem. The recipient resets its real time clock using the data in themessage, and responds with an ACK (acknowledged) or NAK (notacknowledged).

-   -   poll→<STX>address, TS, year, month, day, hour, minute, second,        millisecond, CS<ETX>    -   the year is 2 digit    -   response→ACK or NAK        RS—Reset Accumulators Command

The Reset Accumulators Command can be initiated by any microcontrollerin the system. The Recipient resets its energy accumulators, andresponds with an ACK or NAK.

-   -   poll→<STX>address, RS, CS<STX>    -   response→ACK or NAK        FT—FFT Coefficients Request    -   not programmed        WV—Voltage Waveform Request    -   not programmed        WA—Current Waveform Request    -   not programmed        AH—Historical Data Request

The Analog History Data Request can be initiated by any microcontrollerin the system. The recipient responds with the data block requested.

-   -   poll→<STX>address, AH, channel, number of values, start year,        start month, start day, start hour, start minute, CS<ETX>    -   valid channel numbers are 0 to 26;    -   requests X number of values starting at (and including) the        start time and going back in time (reverse chronological order);        e.g., <STX>address, AH, 0, 3, 4, 4, E, 2, 2D, CS<ETX>will return        (with a logging interval of 15 minutes) the three values for        channel 0 for Apr. 14, 2004 at 2:45, 2:30 and 2:15 in that        order;    -   the time is optional (all or nothing—all time fields fill in or        none of them)—if empty, the start time is the time of the most        recent logged value for the channel;    -   maximum number of values returned is 50 (it accepts requests for        more but will only return 50).    -   response→<STX>address, AH, channel, logging interval, number of        values, start year, start month, start day, start hour, start        minute, most recent value, . . . , least recent value, CS<ETX>    -   maximum of 50 values in the response, regardless of the number        requested;    -   the number of values may be less than the number requested if        the number of values requested is less than the number of values        available (e.g. asking for older data than is stored in the        device).        MH—Metering Historical Data Request

The Metering History Data Request can be initiated by anymicrocontroller in the system. The recipient responds with the datablock requested.

poll→<STX>address, MH, channel, number of values, start year, startmonth, start day, start hour, start minute, CS<ETX>

-   -   channels are: voltage=0, current=1, watts=2, vars=3, phase        angle=4.    -   response→<STX>address, MH, channel, logging interval, number of        values, start year, start month, start day, start hour, start        minute, CS<ETX>        HD—Delete Historical Data Command

The Delete Historical Data Command can be initiated by anymicrocontroller in the system. The recipient responds with and ACK forsuccess or NAK for failure to carry out the command. The main controllerdeletes the specified historical data.

poll→<STX>address, HD, CS<ETX>

-   -   response→ACK if ok        SN—Serial Number Request

The Serial Number Request can be initiated by any microcontroller in thesystem. The recipient responds with the data block requested.

-   -   poll→<STX>address, SN, CS<ETX>    -   response→<STX>address, SN, serial number, CS<ETX>        AD—Address Configuration Command

The Address Configuration Command can be initiated by anymicrocontroller in the system. The recipient responds with and ACK forSuccess or NAK for failure to carry out the command. Both the maincontroller and the power supply controller change their communicationsaddress in response to this command.

-   -   poll→<STX>address, AD, new address, CS<ETX>    -   response→ACK    -   note that the address in the ACK message is the old address.        AC—Analog Configuration Request

The Analog Configuration Request can be initiated by any microcontrollerin the system. The recipient responds with the data block requested.

-   -   request→analog configuration    -   poll→<STX>address, AC, channel, CS<ETX>    -   channel is 0 to 26.    -   response→<STX>address, AC, channel, logging interval, channel        enabled, multiplier, offset, upper bound engineering, lower        bound engineering, CS<ETX>    -   channel enabled value is 0 for not enabled, 1 for enabled;    -   logging interval is integer, all conversion fields are floating        point;    -   conversion fields may be empty, for example, if the conversion        uses a multiplier and offset then upper and lower bound fields        will be empty and if the conversion uses upper and lower bounds,        the multiplier and offset fields will be empty;    -   if all conversion fields are empty it assumes a multiplier of 1        and an offset of 0 (no upper and lower bounds);    -   logging intervals are in minutes. A 0 in this field or an empty        field means that the channel is not logged;    -   valid logging intervals are 1, 5, 10, 15, 30 and 60 minutes.        AC—Set Analog Configuration Command

The Analog Configuration Command can be initiated by any microcontrollerin the system. The recipient accepts the input data block to replace thecurrent configuration information.

-   -   poll→<STX>address, AC, channel, logging interval, channel        enabled, multiplier, offset, upper bound engineering, lower        bound engineering, CS<ETX>    -   response→ACK or NAK        MC—Metering Configuration Request

The Metering Configuration Request can be initiated by anymicrocontroller in the system. The recipient responds with the datablock requested.

-   -   request→metering configuration    -   poll→<STX>address, MC, CS<ETX>    -   response→<STX>address, MC, volts logging interval, volts        multiplier, volts offset, volts upper bound engineering, volts        lower bound engineering, current logging interval, current        multiplier, current offset, current upper bound engineering,        current lower bound engineering, watts logging interval, watts        multiplier, watts offset, watts upper bound engineering, watts        lower bound engineering, vars logging interval, vars multiplier,        vars offset, vars upper bound engineering, vars lower bound        engineering, phase angle logging interval, voltage gain, current        gain, fall scale input, line frequency, phase angle error,        CS<ETX>    -   voltage gain, current gain, full scale input and line frequency        are integers, everything else is the same as in the analog        configuration message.        MC—Set Metering Configuration Command

The Metering Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, MC, volts logging interval, volts multiplier,        volts offset, volts upper bound engineering, volts lower bound        engineering, current logging interval, current multiplier,        current offset, current upper bound engineering, current lower        bound engineering, watts logging interval, watts multiplier,        watts offset, watts upper bound engineering, watts lower bound        engineering, vars logging interval, vars multiplier, vars        offset, vars upper bound engineering, vars lower bound        engineering, phase angle logging interval, voltage gain, current        gain, full scale input, line frequency, phase angle error,        CS<ETX>    -   response→ACK or NAK        EC—Energy Configuration Request

The Energy Configuration Request can be initiated by any microcontrollerin the system. The recipient responds with the data block requested.

-   -   request→energy configuration    -   poll→<STX>address, EC, CS<ETX>    -   response→<STX>address, EC, logging interval, Whr in enabled, V        Arhr in enabled, Whr out enabled, V Arhr out enabled, reset time        year, reset time month, reset time day, reset time hour, reset        time minute, reset time second, CS<ETX>    -   0 for not enabled, 1 for enabled;    -   logging interval is for future use;    -   reset time is for all accumulated values and is defined by        filling in the appropriate fields;    -   filling in month, day, hour, minute and second will cause        accumulators to reset yearly on the given day and time;    -   filling in day, hour, minute, second will cause accumulators to        reset monthly on the given day and time;    -   filling in hour, minute, second will cause accumulators to reset        daily at the given time;    -   filling in all of the time fields, including the year, will        cause it to reset only once.        EC—Set Energy Configuration

The Set Energy Configuration Command can be initiated by anymicrocontroller in the system, The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, EC, logging interval, Whr in enabled, V Arhr        in enabled, Whr out enabled, V Arhr out enabled, reset time        year, reset time month, reset time day, reset time hour, reset        time minute, reset time second, CS<ETX>    -   response→ACK or NAK        DC—Configuration Request

The Digital Configuration Request can be initiated by anymicrocontroller in the system. The recipient responds with the datablock requested.

-   -   request→digital configuration    -   poll→<STX>address, DC, CS<ETX>    -   response→<STX>address, DC, channel 0 logged, channel 1 logged, .        . . channel 27 logged, CS<ETX>    -   0 for not logged, 1 for logged.        DC—Set Digital Configuration

The Set Digital Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, DC, channel 0 logged, channel 1 logged, . . .        , channel 27 logged, CS<ETX>    -   response→ACK or NAK        WC—Waveform Capture Configuration Request    -   not programmed        WC—Waveform Capture Configuration Command    -   not programmed        PC—Serial Port Configuration Request

The Serial Port Configuration Request (for the extra port, not the radioport) can be initiated by any microcontroller in the system. Therecipient responds with the data block requested.

-   -   request→serial port configuration    -   poll→<STX>address, PC, port, CS<ETX>    -   response→<STX>address, PC, port, baud rate, parity, data bits,        stop bits, CS<ETX>    -   port is always 1;    -   if the port is not in use then all of the setup fields are        empty;    -   parity is 0 for even, 1 for odd and 2 for none;    -   data bits are 7 or 8;    -   stop bits are 1 or 2.        PC—Set Serial Port Configuration

The Set Serial Port Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, PC, port, baud rate, parity, data bits, stop        bits, CS<ETX>    -   response→ACK or NAK        SC—Site Specific Configuration Request

The Site Specific Configuration Request can be initiated by anymicrocontroller in the system. The recipient responds with the datablock requested.

-   -   request→site specific configuration    -   poll→<STX>address, SC, CS<ETX>    -   response→<STX>address, SC, voltage multiplier, phase angle        offset, CS<ETX>    -   floating point engineering values.        SC—Set Site Specific Configuration

The Set Site Specific Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, SC, voltage multiplier, phase angle offset,        CS<ETX>    -   response→ACK or NAK        BC—Battery Charger Threshold Configuration Request

The Battery Charger Threshold Configuration Request can be initiated byany microcontroller in the system. The recipient responds with the datablock requested.

-   -   request→battery changer configuration    -   poll→<STX>address, BC, CS<ETX>    -   response→<STX>address, BC, battery changer threshold, CS<ETX>    -   floating point engineering value.        BC—Set Battery Charger Configuration

The Set Battery Charger Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, BC, battery changer threshold, CS<ETX>    -   response→ACK or NAK        CA—Offset Calibration Command

The Set Offset Calibration Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, CA, CS<ETX>    -   perform a calibration.    -   response→ACK or NAK        or,    -   poll→<STX>address, CA, 0, CS<ETX>    -   reset voltage and current offsets to 0.    -   response→ACK or NAK        LO—Start Loader Command

The Start Loader Command can be initiated by any microcontroller in thesystem. The recipient accepts the input data block to replace thecurrent configuration information.

-   -   poll→<STX>address, LO, CS<ETX>    -   response→sends an ACK then starts the loader        SA—Save Configuration Command

The Save Configuration Command can be initiated by any microcontrollerin the system. The recipient accepts the input data block to replace thecurrent configuration information.

-   -   poll→<STX>address, SA, CS<ETX>    -   saves the configuration to EEPROM.    -   response→ACK or NAK        AS—Autoscaling Configuration Command

The Autoscaling Configuration Command can be initiated by anymicrocontroller in the system. The recipient accepts the input datablock to replace the current configuration information.

-   -   poll→<STX>address, AS, volts engineering, current engineering,        CS<ETX>    -   performs autoscaling.    -   response→ACK or NAK        SP—Send Power Supply Data Command

The Send Power Supply Data request is initiated by the power supplycontroller and is sent to the main controller.

-   -   poll→<STX>address, SP, power supply voltage, power supply        temperature, shunt voltage, CS<ETX>    -   from power supply to main controller;    -   response→<STX>address, SP, CS<ETX>    -   from main controller to power supply;    -   all values are 16 bit integer “raw” readings.        GP—Get Power Supply Data Command

Receives Power Supply data from the main controller (for verification).

-   -   Command: “GP”    -   Data: None    -   Response: “GP”    -   Data: Power supply voltage (16-bit raw reading)    -   Power supply temperature (16-bit raw reading)    -   Shunt voltage (16-bit raw reading)        GS—Get Main Controller Status Request

Returns alarm and other status information from the main controller. Thepower supply controller polls the Main controller, which returns thedata to the power supply:

-   -   poll→<STX>address, GS, CS<ETX>—from power supply to main        controller    -   response→<STX>address, GS, X, CS<ETX>    -   where X is 0 for no alarms, 1 if there is an alarm. The power        supply needs only the presence or absence of alarms—“call home”        or don't call home.        OL—Line Status Report

The power supply needs to send a message to the main controller when itconnects to the ground station.

-   -   poll→<STX>address, OL, CS<ETX>—from power supply to ground        station    -   response→the ACK message        AA—Analog Alarm Configuration Command

The Analog Alarm Configuration Command is sent from an externalprocessor to provide alarm set up parameters to the main controller.

-   -   poll→<STX>address, AA, channel, low alarm level, high alarm        level 1, high alarm level 2, high alarm level 3, alarm        dead-band, CS<ETX>    -   response→ACK message        MA—Metering Alarm Configuration Command

The Metering Alarm Configuration Command is sent from an externalprocessor to provide alarm set up parameters to the main controller.

-   -   poll→<STX>address, MA, channel, low alarm level, high alarm        level 1, high alarm level 2, high alarm level 3, alarm        dead-band, CS<ETX>    -   response→ACK message        AR—Alarm Report Status

The Analog Alarm Report Status is sent in response to a poll from thepower supply controller.

-   -   poll→<STX>address, AR, CS<ETX>    -   response→<STX>address, AR, first channel alarm type, first        channel alarm value, . . . , last channel alarm type, last        channel alarm value, CS<ETX>    -   where the “alarm type” is 1 for low, 2 for high alarm level 1, 3        for high alarm level 2, 4 for high alarm level 3 and “alarm        value” is the value that caused the alarm.        MS—Analog Alarm Status

The Metering Alarm Status report is sent in response to a poll from thepower supply controller. Metering alarms need not be polled as often asanalog alarms.

-   -   poll→<STX>address, MS, CS<ETX>    -   response→<STX>address, MS, first channel alarm type, first        channel alarm value, . . . , last channel alarm type, last        channel alarm value, CS<ETX>    -   where the “alarm type” is 1 for low, 2 for high alarm level 1, 3        for high alarm level 2, 4 for high alarm level 3 and “alarm        value” is the value that caused the alarm.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,because certain changes may be made in carrying out the above method andin the construction(s) set forth without departing from the spirit andscope of the invention, it is intended that all matter contained in theabove description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall there between.

What is claimed:
 1. An apparatus for monitoring the operation of anelectric power conductor, comprising: a housing having a toroidal shapeand means for mounting on said electric power conductor; a plurality ofelectrical instruments in said housing for monitoring various parametersassociated with the conductor; recording means in said housing forrecording the various parameters being monitored; and analyzing means insaid housing for analyzing disturbance and fault events based on thevarious parameters being monitored, wherein said analyzing meansproduces fault location reports based on the various parametersmonitored from one end of the conductor.
 2. The apparatus according toclaim 1, wherein the plurality of electrical instruments include: meansfor measuring an electric current flowing through the conductor; meansfor measuring an electric potential (voltage) of the conductor relativeto a ground potential; and means for determining a phase relationshipbetween the measured current and voltage.
 3. The apparatus according toclaim 1, further comprising means for receiving a global positioningsignal (GPS) for use by said analyzing means.
 4. The apparatus accordingto claim 3, wherein the signal from the GPS provides a signal fortime-stamping the various parameters being monitored.
 5. The apparatusaccording to claim 1, further comprising power means in said housing forpowering the apparatus by induction from an electromagnetic fieldproduced by the energized conductor.
 6. The apparatus according to claim5, wherein said power means includes: energy storage means for poweringsaid apparatus when the electromagnetic field produced by the energizedconductor is below a first threshold level; and charging means forcharging the energy storage means by induction when the electromagneticfield exceeds a second threshold level.
 7. The apparatus according toclaim 1, wherein the plurality of electrical instruments includes: meansfor measuring a temperature of the conductor; means for sensing a pitchangle of the conductor; means for sensing motion perpendicular to alongitudinal axis of the conductor.
 8. The apparatus according to claim1, further comprising updating means for updating a programming of theanalyzing means without removing the apparatus from the power conductor.9. The apparatus according to claim 1, wherein the housing is enabled tobe mounted while the conductor is energized.
 10. An apparatus formonitoring the operation of an electric power conductor, comprising: ahousing having a toroidal shape and means for mounting on said electricpower conductor; a plurality of electrical instruments in said housingfor monitoring various parameters associated with the conductor;recording means in said housing for recording the various parametersbeing monitored; and analyzing means in said housing for analyzingdisturbance and fault events based on the various parameters beingmonitored, means for transmitting and receiving the various parametersbeing monitored to another apparatus at a different location on theconductor, wherein said analyzing means produces fault location reportsbased on the various parameters monitored from different locations onthe conductor.
 11. An apparatus for monitoring the operation of anelectric power conductor, comprising: a housing adapted to be mounted onsaid electric power conductor; a plurality of electrical instruments insaid housing for monitoring various parameters associated with theconductor; recording means in said housing for recording the variousparameters being monitored; and analyzing means in said housing foranalyzing disturbance and fault events based on the various parametersbeing monitored, wherein said analyzing means produces fault locationreports based on the various parameters monitored from one end of theconductor.
 12. An apparatus for monitoring the operation of an electricpower conductor, comprising: a housing adapted to be mounted on saidelectric power conductor; a plurality of electrical instruments in saidhousing for monitoring various parameters associated with the conductor;recording means in said housing for recording the various parametersbeing monitored; and analyzing means in said housing for analyzing realtime processes and disturbance and fault events based on the variousparameters being monitored, wherein said analyzing means produces faultand fault location reports based on the various parameters monitoredfrom one end of the conductor.